Aim 2. Measure coronary blood flow using Regadenoson stress CMR to determine the MBF reserve in type 1 DM subjects compared to non-diabetic controls. Using the method of a two compartment model with K trans function analysis, we will determine the myocardial blood flow reserve by cardiac MR. This approach will use regadenoson bolus as the vasodilator for the hyperemic response of the coronary arterial bed. We will assess the relationship of MBF reserve or lack of reserve to disease state i.e T1D to non-DM subjects. In addition we will regionally compare MBF reserve to the MP index obtained from radionuclide techniques by coronary vascular territories. Similarly CAC values obtained at the 6-yr CACTI follow-up study will be directly compared to blood flow measurement within coronary vascular distributions.